Newly manufactured vehicles, after production, may be parked on a production plant parking lot before they are delivered to dealerships for sale. These vehicles may also be filled with low octane fuels and may be parked for longer durations at the production plant parking lot, and later, at a dealership lot before they are sold. As such, lower octane fuels can cause pre-ignition events during engine operation resulting in engine degradation. Pre-ignition events may also be triggered by aggressive driving such as driving that can occur when moving vehicles for short distances around production plant parking lots. In addition to pre-ignition, spark plugs in engines in the new vehicles may also be susceptible to degradation. As an example, spark plugs may experience fouling due to the presence of rich combustion conditions when engines are cold started. Further, as engine run times may be shorter when newly manufactured vehicles are moved around the production plant parking lot, carbon deposits on the spark plugs may not be burned off leading to fouling of the spark plugs. Thus, engine degradation in newly manufactured vehicles may occur due to pre-ignition as well as spark plug fouling.
The inventors herein have recognized the above issues and identified an approach to at least partly address the above issues. An example method may comprise, during a pre-delivery phase of a vehicle including an engine, operating the engine with a first setting for air/fuel ratio to reduce spark plug fouling, and adjusting the first setting of the air/fuel ratio responsive to pre-ignition. In this way, spark plug fouling and pre-ignition may be simultaneously controlled.
For example, a boosted engine in a newly manufactured vehicle may be operated with a pre-delivery calibration during a pre-delivery phase. The pre-delivery phase may include a phase between production and delivery to a dealership. In another example, the pre-delivery phase may include a mileage that is lower than a pre-determined threshold. The pre-delivery engine calibration may include a first setting for air/fuel ratio that is leaner than stoichiometry in order to reduce spark plug fouling. In response to indication of pre-ignition, the first setting for air-fuel ratio may be adjusted from leaner than stoichiometry to richer than stoichiometry. Further still, the air/fuel ratio may be re-adjusted to a leaner than stoichiometry ratio if spark plug fouling is detected. As such, engine conditions may be modified actively to control pre-ignition as well as spark plug fouling at the same time.
In this way, an engine in a newly manufactured vehicle may be controlled to diminish pre-ignition and spark plug fouling. By using a leaner than stoichiometric air/fuel ratio as the first setting in the pre-delivery calibration, rich combustion conditions during engine cold starts may be reduced leading to fewer deposits on the spark plug. In response to pre-ignition, the leaner than stoichiometric air/fuel ratio may be adjusted to a richer than stoichiometric air/fuel ratio. By enriching combustion in the engine, pre-ignition may be mitigated. Thus, engine operation may be controlled to decrease spark plug fouling and engine operation may be further adjusted to address pre-ignition. As a result, engine degradation in the pre-delivery phase due to pre-ignition and spark plug fouling may be reduced.
It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.